Friday, January 1, 2010

Reaming, Gluing, and Grousing

As I was thinking about ways to rectify The Mystery of the Too Small Bracket Hole, I decided that I might not have to remove all of the stuff that holds those brackets onto the horizontal stab. It was, after all, just the two inner-most holes (one for each bracket) that needed to be embiggened. The outer holes have the threaded end of the bolt go through them, and that part fits just fine.

Still, that left the issue of getting a 1/4" drill bit and the great bulky mass of the drill holding (and turning) it down into the area between the bracket and that massive counterbalance arm. I resolved that problem by forgoing the use of the drill. I just started the bit into the hole by hand, then used a pair of pliers to get a good enough grip to turn the bit manually. It was fairly easy - there was only a tiny bit of aluminum to be removed. Once done, the bolts fit in like a new Koi in a crowded pond.

That's when I found out that even with the new tweezers I couldn't get a grip on those washers. I cheated a bit and used the method called out in the next step, which is to hold them in place with a tiny bead of super glue. The plans have you do that once you have determined the correct size washers to use, but if you make the drop of glue small enough, it will break away easily as you test fit with various sized washers. Mine ended up fitting just fine with the default -L (thin) washers. I left them glued into place after removing the bulkhead. There's less chance of them getting lost that way, at least as long as I keep the bolt in there too.

So, at long last, on to page 10-06! Where, not surprisingly the way things have been going for the last couple of days, I immediately ran into a problem. Here you can see that the F-1284-R is supposed to mount to the F-1283B:

Four little holes on a bitty little part - what could go wrong? Well, the holes didn't line up. And, as we know, if it doesn't fit right, then it probably isn't being done right. What does fit perfectly well, though, is the F-1284-L:

It would seem, therefore, that there is a mistake in the plans! If that was the case though, surely a revision page would have been released by now to clear up the situation, but that page has not been revised since the day it was drawn/written.

My faith thus called into question, I'm unsure as to how to proceed. The first step will be to consult with other RV-12 builders via their build notes on web sites here and there and see if anyone else has tripped over this. That's very likely to bear fruit, but if not, I will have to consider other options. I can't start putting together the tail cone pieces until this is resolved, but with the 20F temps today, I'm not sure I want to brave the frigid hangar anyway.

For those reading, I'm not sure if Dave ever posted the results of the question regarding F-1284-L/R on another blog post, but Vans has confirmed that the plans are reversed on page 10-6. F-1283B goes with F-1284-L and F-1283A goes with F-1284-L (no idea why they haven't fixed this typo in the plans in 10+ years).

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